/*
 * Copyright (C) 2012 ARM Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef ASM_STACKTRACE_H
#define ASM_STACKTRACE_H

#include <seminix/sched/task_stack.h>
#include <seminix/percpu.h>
#include <asm/ptrace.h>

struct task_struct;

struct stackframe {
    unsigned long fp;
    unsigned long pc;
};

enum stack_type {
    STACK_TYPE_UNKNOWN,
    STACK_TYPE_TASK,
    STACK_TYPE_IRQ,
};

struct stack_info {
    unsigned long low;
    unsigned long high;
    enum stack_type type;
};

extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk);

DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);

static inline bool on_irq_stack(unsigned long sp,
                struct stack_info *info)
{
    unsigned long low = (unsigned long)raw_cpu_read(irq_stack_ptr);
    unsigned long high = low + IRQ_STACK_SIZE;

    if (!low)
        return false;

    if (sp < low || sp >= high)
        return false;

    if (info) {
        info->low = low;
        info->high = high;
        info->type = STACK_TYPE_IRQ;
    }

    return true;
}

static inline bool on_task_stack(struct task_struct *tsk, unsigned long sp,
                struct stack_info *info)
{
    unsigned long low = (unsigned long)task_stack_page(tsk);
    unsigned long high = low + THREAD_SIZE;

    if (sp < low || sp >= high)
        return false;

    if (info) {
        info->low = low;
        info->high = high;
        info->type = STACK_TYPE_TASK;
    }

    return true;
}

/*
 * We can only safely access per-cpu stacks from current in a non-preemptible
 * context.
 */
static inline bool on_accessible_stack(struct task_struct *tsk,
                    unsigned long sp,
                    struct stack_info *info)
{
    if (on_task_stack(tsk, sp, info))
        return true;
    if (tsk != current || preemptible())
        return false;
    if (on_irq_stack(sp, info))
        return true;
    return false;
}

#endif	/* !ASM_STACKTRACE_H */
